Detection of HIV p24 from antigen presenting monocytes for early diagnosis of HIV-1 infection.

The monocytic/macrophagic lineage has an antigen presenting cell function also towards HIV. On the basis of this fact, a new method, indirect immunofluorescence (IIF) for measurement of p24 from monocytes was used. The results were compared to an amplified enzymatic test for serum dissociated p24 detection in 14 HIV negative individuals at risk for HIV and 12 HIV positive patients. Only one seronegative, who had a symptomatic primary HIV infection, had a positive IIF and also an elevated level of p24 in serum. The others had a negative IIF and, 6 months after the specimen, were not positive to the routine methods for detection of anti-HIV antibodies. Seronegative subjects not at risk for HIV were consistently negative to IIF. Among the HIV positive patients 4 were positive to IIF and the remaining 5 were positive to routine methods. Divergent results could be explained by the fact that one test measures cell derived antigen and the other serum antigen and that monocytes can loose APC function in the advanced stages of the illness. The test proved to be cheap and simple, and it is possible to hypothesize an application of it as a support test for the early diagnosis of HIV infection in laboratories not endowed with high levels of technology. Moreover, the results of the amplified p24 ELISA test in 44 seronegative at risk test are reported herein.